1. Field of the Invention
This invention relates to silicone rubber composition and to silicone rubber. This invention also relates to a method of improving the flame retardancy of a silicone rubber.
2. Background Information
The silicone rubber art is filled with methods and additives which are designed to improve the properties of the silicone rubber. Many of these methods and additives are complex, expensive, and difficult to use. For example in the art of making silicone rubber flame retardant, platinum compounds are added to the silicone rubber composition. Platinum is expensive even in small amounts. Because the amounts of platinum used are small, parts per million, and because it is susceptible to poisoning, care must be taken to avoid materials and environments which can poison the platinum thus making it ineffective as a flame retardant. However, platinum alone is not enough for most applications and additional ingredients are needed to further improve the flame retardant property These additional ingredients might be the rare earth oxides and hydroxides which are also expensive. Other additives which can be used are carbon black and fumed titanium dioxide. The carbon black, although effective in improving the flame retardant property, only allows the production of black or grayish products and many applications require transparent materials or a color other than black or gray, such as in electrical insulation for wiring. Some of the means used to improve the flame retardancy of the silicone rubber destroy the physical properties of the silicone rubber to such a great extent that the silicone rubber becomes unusable for the application for which it was designed.